An improved method for preparing DNA from human brain

The preparation of DNA from human brain by conventional protease and RNAase digestion, phenol-chloroform extraction and ethanol precipitation results in very low yields. This is probably due to interference by lipid present at very high levels in this tissue. We have overcome this by solubilizing the initial tissue homogenate by heating at 60 degrees C for 30 min in sodium dodecyl sulphate. This results in a threefold increase in yield and a considerable reduction in preparation time. The molecular weight of the DNA is greater than 20 X 10(6) milion.